On Wed, 23 Mar 2011 10:51:00 -0600, Bobby wrote:
Hello all.
I've been having trouble figuring this out so. Thought I'd ask the
experts!
Using Squid 2.7 with no ACL's configured to block media or file
extensions for download. When users try to download a .PDF for
example; the download will start and then hang about halfway through.
After hanging for a minute or so the download box will disappear,
when
the file is checked as you might guess it is incomplete. On occasion
I
can just click on the file to download and it will complete
successfully. More times than not though it will just never work and
I
have to bypass the proxy to download the file. I have similar issues
with flash and other types of video content. As an example: I can go
to CNN or Youtube and click on a video file, the file will start to
play and then just stop.. Hanging as long as I leave the page open.
As
a test I've left the page up all day before and sometimes it will
just
start playing hours later, sometimes it never restarts..
Another problem I've noticed that may be related; this hang seems to
happen even on a regular web page such as google.com. I launch the
browser and go to google, the page loads but the browser is
unresponsive (progress bar sticks about  of the way across) 30
seconds to a minute later the progress bar hits 100% and the page and
browser are responsive. I have noticed that during a page hang like
this if I am logged into the squid box (Debian Lenny) and I issue a
"rndc flush" command the progress bar completes to 100% and the page
is immediately responsive.
Any ideas?
Is the request speed going through this proxy under 1 or 2 per second?
That hanging behaviour reminds me of a scheduling issue older Squid had
under very low traffic (ie only one client).
The other common problem with largish files is window scaling or ECN
problems. Where one end of the connection would work until it increased
the TX window to a certain size, then an ICMP control message would
disappear and everything would hang.
http://wiki.squid-cache.org/KnowledgeBase/BrokenWindowSize
The incomplete PDF issue is identical to one I'm struggling with myself
for one client. It seems to be occasional (1 in 10 or so) and something
to do with the Acrobat fetch algorithms for us though.
HTH
Amos
